Thatcher Calculator K & E Keuffel & Esser #4014 Pocket Watch Calculator / Slide Rule Larry & Carole Meeker
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Antique & Vintage
Calculation Devices / Slide Rules & Related

We Buy Scientific and Calculation Related Antiques & Collectibles!!

We buy, sell, and deal in early and unusual slide rules, calculators and other early patented calculation devices. We also buy many Antique French Calculatorother office related antiques and collectibles. We specialize in tools and technology related antiques from the home, shop, farm, or office. We are full time antique dealers of early scientific and technology related antiques and actively deal in a broad range of related antiques, collectibles and related advertising.

This site, is our informational and past sales results website. There are links on the left to informational pages, and on the right are links to past sales results for many scientific related antiques we haveGordons 
	Addometer / Calculator sold.

Our antique sales site for these and other types of antiques and collectibles is  Please visit it that site if you are looking to buy these types of antiques and collectibles.

Please contact us by email at if you have interesting technological or scientific related antiques you want to sell.

Curta Calculators

Pictured are two versions of the ever-popular Curta calculator. On the left is a Type II Curta and below is a Type I Curta. curta calculatorThe main difference is type 2 Curta calculator has a larger capacity. These calculating devices were first designed during WWII and were introduced shortly after the Second World War. They were still being made right up to the time the hand-held electronic calculator caused their popularity to wane and production to end in the 70's.

They originally retailed for about $150.00.  For most of the 70's and into the 80's examples sat on shelves and in back storerooms of drafting supply shops as dead stock. After word got out that they were being collected and a constant supply and demand became available on the internet, pricescurta calculator skyrocketed to $1000.00 or more. 

Years ago these devices could be had for a couple hundred dollars and there were more than enough to go around.  The supply seemed endless, and the demand scant. The Internet auctions came and the market changed with a new group of collectors entering the market.  They are a popular collectible and demand is pretty constant with prices for them ranging anywhere from $600-2500.00 or so depending on a few variables.  I have a nice Curta II listed for sale on for around $1200.00.  Results for French and German examples sold on eBay generally sell for $1500.00 - 2500.00 if you believe what you see.  I do not.

Antique Calculator Values

The prices of most later modern electronic calculators also took off for a while and reached unheard of Antique Adding Machinevalues when demand rose right after the internet came into vogue.  The market for electronic hand-held calculators from our school days evolved during this period. Many of those values dropped considerably after the tech bubble burst.

The one caveat being the rare of the rare still do well with the prime example being the Apple 1 computers selling for half a million or so.  Results like that are explained by some folks simply having too much money.

I like, and still look for these handheld electronic calculators, but rarely do I want the larger later and more typically seen  modern 10-keySimplicitas
	Addizonartrice Adding Machine model calculators or adders, electric or mechanical, like those from the 30's or 40's or later.  Including large Victors, Burroughs, and a host of the other later 10-key heavyweight adding machines that seem to be in every garage and in every antique booth and even at the end of some ropes in the bottom of people's boats acting as ballast or anchors. There are people who do collect and are looking for these later machines, but I do not know them and have no market to sell them.  Check eBay to see what most of these later 20's - 60's era calculators / adders actually sell for and you will see what I mean.

Early Calculation Devices

Antique and vintage calculating devices have had an interesting and varied period of development through the years.  Every Universal Adder Patented July 15th 1890one is familiar with the abacus, one of the earliest of all calculating devices. 

Another early form of a calculator first developed  for Western civilizations was known as Napier's Bones.  These were cubes or dice-like in shape, and were made  from bones or ivory and real examples are extremely rare and collectible.  They are being reproduced today and sold at various internet sites and auctions, at times with no indication of their true vintage.  Be aware.

Logarithmic scales found on slide rules were first introduced by Routledge in the early 1800's and were incorporated intoantique double wheel calculator the various forms of rules and other devices that were the forerunner to the slide rule as we know it today.  These scales were typically found on rules during the early to mid 1800's primarily for use by merchants and trades people who needed a viable way to run larger calculations for their business.

One of the first types of mass produced calculating devices that still survive in numbers today are paper tables with wheels and dials similar to the adder that is pictured above on the right.  The Palmer's Computing Scale (not shown) is the best known and most commonly seen of these types of early paper calculators.

Early Dial type calculators / adders were around pretty much during the same period.  The best known of this style machine hart_caluculateris the well known Webb Adder which was  patented in  the late 1800's.  These were produced in a few different configurations throughout the years, with the earliest versions having a wooden back.  Below is a later version marked with the maker'swebb-adder name and patent date. There are early knockoffs of this calculator / adder that are not marked that can found as well.  They were produced to compete with the real things, much as the pirated tapes and CDs that abound in today's markets.

On the left  is a pretty rare and earlier model adder / calculator with this same basic configuration as those above.  It is known as the Hart Patent Adder.

I am an active antique dealer in early or antique calculation devices and looking to add nice examples to the sale pages on our sales website located at I am interested in any of these kinds of early dial calculators,  sliding style calculators, or circular calculators like the one in the top left corner.

Key Type Calculation Devices

Near the turn of the century dials began to give way to key type adders and calculators, or those with stepped drum and Burroughs Glass Side Adding Machine / Calculatorpinwheel style mechanisms, and when these stepped drum and pin-wheel models became more economically feasible to manufacture, even though they were invented years earlier they soon dominated the market.

This style calculating machine, which quickly and easily performed four functions, became the standard. Shortly thereafter calculators became electrified and all of these old style calculators were pretty much relegated to the status of obsolete but not necessarily collectible.  Millions had been produced and they are still readily available.

There is a very informative and well done site that is primarily focused on the history of the Hewlett Packard line of calculators, but they also have a very nice and well done history of earlier calculation devices leading up to the HP line.1st model wood comptometer A more detailed history of this period can be found at The Museum of HP Calculators.  It is interesting reading and should be looked into if you are trying to identify your calculator. 

The most famous, and most commonly found early key style calculating machines is the Comptometer. It was a very popular machine in its day, as attested to by the sheer number still available. The most common versions are found in a tan metal case and sell for under $100 in most cases.  The earliest version came housed in a wooden case like the one pictured on the right and is much harder to find. These 1st model comptometers have been known to sell for several thousand depending on condition, serial number, and other factors.
calcumter / adding machine
Other non electric calculators considered collectible operated with the  stepped drum or pin-wheel mechanism. Some of the names of these style machines are the Marchant, Odhner, Time is Money (TIM), The Millionaire Calculator, The Peerless Reckoning Machine which was sold by K & E, as well as a host of others that were being produced early on.  In general the earlier the better, with some selling for 1000.00 or more and others 100 or less. 

Slide Rules, Calculators
& Other Scientific Related Antiques

Below are some pictures of the types of scientific antiques and vintage calculation devices and slide rules that weFuller Calculator / Circular Slide Rule deal in and are seeking to K & E Webb Stadia Rule / Circular Sliderulebuy.  I am an active antique dealer interested in antique and collectible slide rules and other calculation devices that date from the early 20th century and before.  This page is a basic primer describing the different and various types of scientific and calculation devices we buy, sell, deal in.

Keuffel & Esser Slide Rules

A Basic K & E Slide Rule Cursor Lesson or Beginning Primer for the Curious

The next three pictures give views of different early cursors (the sliding window portion) employed by Keuffel & Esser or K & E and  represent the transition or changes that slide rule cursors have gone through.  This is by no means the full story, and there are variations and other designs by other companies that are not covered here.  1st model Slide Rule cursor

The first picture of the all brass cursor on the right is referred to as the Christmas tree or chisel point cursor. This style cursor is considered the first model K & E used and dates from a bit before the 20th century.  It is rare and desirable. It can cause what is otherwise a $10.00 sliderule to sell for several hundred to $1000.00 or more.  It has no glass window like later model slide rule cursors do.  You would work off of one of the tips to do your calculations. Some are like this one with the points going out to just one side and other K & E cursors have points on both sides of the center post or upright.   

The second clam shell cursor picture shows what is known as a clamshell cursor. This was the second cursor employed by K & E. Some examples areK & E Slide Rule pretty rare, others on common rules, are not.  

The clamshell design was replaced by the interesting looking and difficult to find column column cursor which is pictured below on the right.  The column cursors still show in the 1913 catalogs, but were phased out shortly after that. This cursor style was only used for a few short years and affects the value upward for most examples.

The next cursor to be used after the column cursor was the short lived frameless cursor.   (not pictured here) This design was an attempt toK & E Column Cursor save money and material and give the slide rule cursor a sleeker look over the earlier designs.  It was a disaster as they were very fragile and prone to break at the connection points in the corners that had holes drilled through the glass.  This style cursor does not add much of  premium even though it is hard to find them not broken or damaged.

K & E shortly thereafter introduced the standard framed cursor that most slide rules found today have.  After K & E introduced their standard framed cursor, that basic design was used until production of slide rules ended in the late 60's or early 70's.

Slide Rules Wanted

I am interested in any slide rule with one of these early all brass cursors pictured above, or slide rules with any other K& E / Keuffel & Esser 4088-2SM Slide Ruleunusual cursors that some other companies used.  Some of these had small decimal keepers or counters on them, or moveable arrows, or in one case a small abacus to help you along with your calculations and in keeping track of where the decimal point belonged. Some also had magnifiers built into the cursor. K & E offered clip on magnifiers. 

I am also interested in any special use slide rules. Slides Rules with scales especially designed for surveying, chemicals, electrical calculations, aviation, radios, and others are sought. 

Slide Rule Values

On the right is a relatively common collectable slide rule put out by K & E or Keuffel & Esser.  It is known as Decilon Slide Rule the Deci-Lon and was one of the last sliderules K & E made or offered.  It is all plastic and was produced for a number of years.  The last models being designated by the model number 68-1100.  Before the Internet this rule could be had routinely for $20 or less and was passed over by collectors and those in  the "know" who were looking for earlier and rarer examples of slide rules. 

For a while this rule routinely sold for $100 or so, not because they are important or scarce, but rather because they are popular. The circular slide rulecollecting frenzy over them and the resulting prices they bring is largely driven by the same impulse that has created a desire for collectibles like GI Joes and Barbie dolls, that being the current generation buying back their childhood, and their memories, rather than anything resembling scarcity or the historical significance.  In this case nerds as opposed to cheerleaders or jocks.  As of 2021 the laws of supply and demand have taken hold, and Deci-Lons are selling for half or less of their highs.  Those who cared got filled up.

The point is that there are many earlier and somewhat rarer slide rules that are not having a lot of attention paid to them these days that have potential to be worth more in the long run, and these are the rules that I am interested in.

Please Contact AntiqBuyer with any early and unusual slide rule that you have and want to sell. Marchant Type Mechanical Calculator

Burkhardt Type A ArithmometeTo see examples of many slide rules and calculators I have sold in the past  go to our sister site at  see examples that we currently have for sale.

If you have or know of one of these earlier and interesting adders / calculators that you want to sell please contact me at

To see examples of similar antiques that we currently have for sale please go to our sister site at and visit the numerous sale pages you will find there. 

Thank you!!
Larry & Carole  

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Larry & Carole Meeker